Harper's office won't say exactly when the overture between the prime minister and Egyptian President Abdel-Fattah el-Sissi took place.
"The Prime Minister has communicated with the president on this case. I'm not going to get into the specifics of the communication between the PM and the president, including the timing or details of that communication," Harper's spokesman Jason MacDonald wrote in an email on Tuesday.
"As you know we have also raised the case at the highest levels of the Egyptian government through the actions of ministers and officials and we will continue to do so."
Opposition Leader Tom Mulcair has called on Harper to "personally" reach out to his Egyptian counterpart to secure the release of a Canadian journalist imprisoned in Cairo.
Mohamed Fahmy was working for satellite news broadcaster Al Jazeera English when he was arrested on Dec. 29, 2013, along with two colleagues.
They were accused of supporting the banned Islamist Muslim Brotherhood group of ousted Egyptian president Mohammed Morsi and were charged with fabricating footage to undermine Egypt's national security.
After a trial that was internationally denounced as a sham, Fahmy was sentenced to seven years in prison. Following an appeal in January, a retrial is set to begin on Thursday.
Mulcair says the Canadian government's efforts to win Fahmy's freedom must not be delayed by the "recent shuffle" of foreign ministers, which was prompted by John Baird's resignation. Minister Rob Nicholson was moved to foreign affairs from defence on Monday.
The NDP leader is calling on Harper to intervene in Fahmy's case, "including by personally reaching out to Egyptian President Abdel-Fattah el-Sissi."
Fahmy's family has launched an online campaign, urging Harper to get involved in the 40-year-old's case.
They have called on supporters to use the hashtag "HarperCallEgypt" in their efforts to push for Fahmy's release.
A Canadian government official, speaking on condition his name not be used, said Harper's communication did not happen on Tuesday and was not in response to the #harpercallegypt campaign.
The Canadian Committee for World Press Freedom has said it backs the call by Fahmy's family for Harper to intervene.
One of Fahmy's colleagues — Australian Peter Greste — was abruptly freed last Sunday under new legislation that allows Egypt's president to deport foreigners convicted or accused of crimes.
Mulcair said Greste's release followed the intensive efforts of the Australian government.
"The Australian prime minister publicly and personally intervened in Mr. Greste's case with success," Mulcair wrote in his open letter to Harper.
Fahmy moved to Canada with his family in 1991, living in Montreal and Vancouver for years before eventually moving abroad for work, which included covering stories for the New York Times and CNN.
He took over as the bureau chief for Al Jazeera's English-language channel in Cairo in September 2013.